With reference to FIG. 1, in conventional bump process, a plurality of bumps 110 are formed on a substrate 100, and each of the bumps 110 comprises a top surface 111 and a lateral surface 112. A connecting layer 120 is formed on the top surface 111 of each of the bumps 110, wherein the bumps 110 are copper bumps, and the connecting layer 120 can be a nickel-gold layer. When the lateral surface 112 of each of the bumps 110 is in contact with water mist, a short phenomenon is occurred between adjacent bumps 110 via electron migration. Besides, for the reason that the top surface 111 of each of the bumps 110 is covered by the connecting layer 120, the corrosion resistant ability of the lateral surface 112 of each of the bumps 110 is far worse than that of the top surface 111. Furthermore, the thinning process of the substrate 100 may lead a bending phenomenon to influence the following test and cutting processes.